rcu: Apply for_each_rcu_flavor() to increment_cpu_stall_ticks()

The increment_cpu_stall_ticks() function listed each RCU flavor
explicitly, with an ifdef to handle preemptible RCU.  This commit
therefore applies for_each_rcu_flavor() to save a line of code.

Because this commit switches from a code-based enumeration of the
flavors of RCU to an rcu_state-list-based enumeration, it is no longer
possible to apply __get_cpu_var() to the per-CPU rcu_data structures.
We instead use __this_cpu_var() on the rcu_state structure's ->rda field
that references the corresponding rcu_data structures.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

1 files changed, 4 insertions, 5 deletions

diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index c47b28bf18ae..70b33bf780f0 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -2200,11 +2200,10 @@ static void zero_cpu_stall_ticks(struct rcu_data *rdp)
 /* Increment ->ticks_this_gp for all flavors of RCU. */
 static void increment_cpu_stall_ticks(void)
 {
-        __get_cpu_var(rcu_sched_data).ticks_this_gp++;
-        __get_cpu_var(rcu_bh_data).ticks_this_gp++;
-#ifdef CONFIG_TREE_PREEMPT_RCU
-        __get_cpu_var(rcu_preempt_data).ticks_this_gp++;
-#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
+        struct rcu_state *rsp;
+
+        for_each_rcu_flavor(rsp)
+                __this_cpu_ptr(rsp->rda)->ticks_this_gp++;
 }
 
 #else /* #ifdef CONFIG_RCU_CPU_STALL_INFO */